In an unverified text message sent last March, Dank told Bombers coach James Hird that players would be injected with the peptide thymosin. Another text in May discusses how an anti-obesity drug would be paid for.

The Herald Sun has previously reported that Essendon removed Dank from his role in mid-2012, over concerns the sports science budget had gone $100,000 over its limit.

Dank is known to have consulted South Yarra doctor Robin Willcourt, who runs the Epigenx Integrated Services in South Yarra, and was questioned by the Australian Crime Commission over the drugs scandal.

In interviews with Fairfax and the ABC, Willcourt admitted an association with Dank, but insisted he spoke with the sports scientist informally about player wellbeing - not performance-enhancing drugs.

However, medical industry sources have told the Herald Sun Dank and Willcourt appeared to have a closer working relationship. They said Dank had been known to answer phones in Willcourt's office and that Willcourt would introduce Dank as a business associate.

In the United States in 1998 Willcourt was convicted for exposing himself to an undercover police officer and ordered to perform 20 hours' community service.

He later claimed he had been caught up in a "sting operation", which he labelled "ridiculous".

Willcourt has not returned the Herald Sun's calls. Nor has Dank.

The owner of Hypermed in South Yarra, Mal Hooper, said he was assisting the Australian Sports and Drug Administration with its Essendon inquiries.

Essendon players used his hyperbaric chambers - which are located opposite Epigenx - between April and July last year.

He said his operation was within the rules and was standard practice among many elite athletes.

"Hyperbaric is not restricted. It is used by many international sporting codes. It's a very common application," he said.